Muscle strength caused by testosterone use is not affected by 5-alpha reductase inhibitors

According to a trial, the 5-alpha reductase inhibitor dutasteride (Avodart) doesn’t influence negatively on fat-free mass in healthy males who take testosterone.
A research linked with this issue was conducted. While fat-free mass was enhanced by 0,6-7,1 kg during 20 weeks in males that used dutasteride and Testosterone Enanthate, fat-free mass was enhanced by 0,8-8,1 kg in those that applied placebo and testosterone. As for muscle strength, sexual functions and volume of prostate, they didn’t differ in men of these 2 groups.
5-alpha reductase inhibitors are used clinically to treat benign prostatic hyperplasia (BPH) and androgenic alopecia. These are disorders which usually affect middle-aged and elderly men.
DHT represents the chief metabolite of testosterone. But the function of DHT in human development is not is not understood. It is supposed that DHT plays vital role in development of prostate and phallus.
Middle-aged and elder males with decreased testosterone levels who apply testosterone medicines have risks connected with reduced muscle mass and sexual troubles.
Nonsteroidal selective androgen receptor modulators (SARMs) are also currently studied and developed. It is confirmed that SARMs and 5-alpha reductase inhibitors are safe because DHT is supposedly not necessary for effects on muscle mass, muscle power and sexual activity. It is also doubted whether DHT has any role for androgen’s effects on hematocrit, hemoglobin, lipids and certain other factors.
Shalender Bhasin and his colleagues at the Boston University have conducted a clinical trial in order to see whether 5?-reduction to DHT is required in order to mediate androgen’s effects on muscle mass. Moreover, the experts evaluated role of 5?-reduction on sexual functions, hematocrit and levels of lipid.
The study conducted by Bhasin and his colleagues implicated healthy males that were 18- 50 years old and had normal levels of testosterone. They administered Testosterone Enanthate and dutasteride or placebo. Measures of Testosterone Enanthate ranged from 50 to 600 mg weekly.
Since 5 ?-reductase inhibitors increase levels of testosterone, all men were given also gonadotropin-releasing hormone agonist in order to block natural testosterone.
The results of the study manifested that fat-free mass was enhanced due to usage of testosterone. It didn’t differ significantly in men of these two groups. Muscle power that was also enhanced due to administration of testosterone didn’t differ between the two groups too. Sexual functions, volume of prostate, sebum production, hemoglobin, acne, hematocrit didn’t differ substantially between those who took placebo and dutasteride.
The experts note that effectiveness of 5?-reductase inhibitors can be limited in men that have normal or high levels of testosterone. That’s why it is necessary to check levels of testosterone in order to determine how bodies will respond to 5 ?-reductase inhibitors.
So, the study has displayed that muscle mass is not affected by 5?-reductase inhibitors.  Males should know that if they have enhanced testosterone levels or introduce exogenous testosterone in their bodies, 5?-reductase inhibitors will not lead to shrunken prostate.